'Embryo atlas' rewrites human development
3D reconstructions of human embryos at (from left to right) 6, 8 and 9.5 pregnancy weeks. [Bernadette de Bakker/Academic Medical Center]
By using light microscopy to study historical human embryo specimens, US-based researchers have created a 3D interactive database that provides new information on the first two months of human development.
Given today's restricted availability of human embryos, verifying existing information on early human development - often more than 100 years old - is difficult.
With this in mind, Dr Bernadette de Bakker from Academic Medical Center, Amsterdam, and colleagues, analysed nearly 15,000 histological sections from the Carnegie Collection of human embryonic specimens.
These samples were collected by medics from around 60 to more than 100 years ago, during procedures such as hysterectomies.
Using Nikon E800 microscopes alongside image analysis software, including Image-Pro Plus and Scope-Pro, Bakker and some 75 researchers imaged, aligned and segmented the sections.
"Because of the large file sizes, stitching and further image processing was performed on PCs with Windows 7 and 16GH RAM," highlights de Bakker.
The researchers then used the 3D reconstruction package, Amira, to create 3D models, that were incorporated into 3D-PDF files, with data analysis also performed on the segmented sections and 3D models.
3D reconstructions of a human embryo at 9.5 pregnancy weeks (15.9 mm in length). From left to right the skin, cardiovascular system, skeleton and all reconstructed organs are presented, [Bernadette de Bakker/Academic Medical Center]
As de Bakker points out, the researchers had identified and labelled around 150 organs and structures from each embryonic specimen, with the 3D models quantifying growth, establishing changes in the positions of organs and clarifying current-day ambiguities.
"[Analyses] of the changing position of just a few structures, such as gonads, kidneys and arteries, shows discrepancies with current textbook, demonstrating the value of the 3D atlas based on the human embryonic specimens," says de Bakker.
The atlas is currently composed of interactive, 3D models of 14 of the embryos, each corresponding to a different stage within the first two months of development.
The researchers hope the atlas will be used to educate medical students, clinicians and researchers interested in human development and development-related disease.
Research is published in Science.